> It’s so different, convoluted, mostly relying on tricks, clean code will slow you down

There’s a seed of truth here, but at the same time, I’ve heard this mostly from people who learned certain programming patterns in school or in enterprise application development, and never learned embedded systems engineering, or just plain didn’t start with game development.

You might be referring to issues with specific game engines, or you might be referring to writing only scripts and plugins for an existing game engine, as opposed to writing a game engine, I don’t know, but generally speaking game coding absolutely can and should be clean. It’s just a different kind of clean than you might expect, if you’re used to thinking in terms of C++ inheritance or functional programming or design patterns you learned elsewhere.